Decommissioning Insight 2015

DECOMMISSIONING INSIGHT 2015

7.1.3 Rig Type There are a number of methods that can be used for platform well P&A and the rig type will depend on whether the original drilling derrick is in place and the water depth where the platform is located. Platform wells are typically plugged and abandoned in phases. The first phase can be rig-less and uses lower cost methods such as wireline, coil tubing or a hydraulic workover unit. This is followed by the second and third phases that are more likely to require a rig. In the CNS and NNS/WofS areas, the majority of platform wells (70 per cent) will be plugged and abandoned using an integral platform rig. By contrast, jack-up rigs are most commonly used (93 per cent) in the SNS and Irish Sea as many of the platforms do not have integral rigs. For subsea wells, the deeper water depths in the CNS and NNS/WofS mean that semi-submersible rigs are typically used, while jack-up rigs will be used in the shallower waters of the SNS and Irish Sea. Figure 11: Forecast Rig Type for Well Plugging and Abandonment from 2015 to 2024 Platform Well P&A

CNS and NNS/WofS

SNS and Irish Sea

2%

2%

1%

Integral Rig

Integral Rig

4%

17%

Jack-Up Rig

Jack-Up Rig

4%

Semi-Submersible Rig

Semi-Submersible Rig

7%

Rig-Less Intervention

Rig-Less Intervention

70%

Not Yet Known

Not Yet Known

93%

Subsea Well P&A

CNS and NNS/WofS

SNS and Irish Sea

2%

2%

Jack-Up Rig

Jack-Up Rig

Jack-Up Rig

7%

7%

12%

Semi-Submersible Rig

Semi-Submersible Rig

Semi-Submersible Rig

5%

Rig-Less Intervention

Rig-Less Intervention

Rig-Less Intervention

Not Yet Known

Not Yet Known

Not Yet Known

83%

91%

91%

Source:Oil &GasUK

Source:Oil &GasUK

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